Knitting machine



March 12, 1946. E. BROOKSBY EI'AL KNITTING MACHINE Filed Aug. 7, 1943 2Sheets-Shea; l

T I fl I I I I I I l u I I l i I I I i i l I i i a? i I l ,0: I g

l v I MInventorAJ MWQ A homey March 12, 1946. BRQQKSBY L 2,396,489

KNITTING MACHINE Filed Aug. 7, 1943 2 Sheets-Sheet 2 lrwenlom,

A ttorneyA v Patented Mar. 12, 1946 I 2,396,489 KNITTING Mnonmn ErnestBrooksby and Frederick Edward Deans, Leicester, England, assignors toThe Bentley Engineering Company Limited, Leicester, England, a Britishcompany Application August 7, 1943, Serial No. 497,826 In Great BritainJuly 20, 1942 Claims.

This invention consists in improvements in or relating to knittingmachines of the type having independently movable needles. Although theinvention is particularly applicable to circular rib machines of thesuperposed cylinder type, it is not limited to such machines, nor is init fact limited to circular knitting machines.

In knitting machines hitherto, feed yarn is so supplied that it is laidinto the hooks of the needles and, in the case of latch needles, asystem of latch guarding devices is necessary in order to ensure thatthe latches are open when yarn is to be fed to the needles.

According to the present invention, a method of supplying a feed yarn toa needle hook consists in laying the yarn on to the front or nose of thehook and thereafter relatively adjusting the hook and the yarn to slidethe latter into the hook.

When the invention is applied to a latch needle the latch, when closed,may be conveniently made so as to project slightly beyond the hook and,should the latch be closed by a loop held by the needle when adjustmentis made to slide the yarn into the hook the yarn will ease the latchopen sufficiently during that adjustment so as to pass between the latchand the hook.

The invention is equally applicable in circumstances in which, in thecase of a latch needle, the-latch is not closed by a previously formedloop.

In one example of the'invention in which a latch needle is used, theneedle and a previously formed loop held by that needle may, prior tosliding the yarn into the hook, be conveniently relatively adjusted to.bring the previously formed loop on to the outside of the latch therebyholding the latter resiliently closed and enabling it to be sprung opensufliiciently to permit the feed yarn to pass between the latch and thenose of the hook.

By the use of this method'of feeding yarn to I the needles it is nolonger necessary to hold open the latches in order tolay the yarn intothe needle hooks, and the usual elaborate system of latch guardingdevices is therefore dispensed with.

In machines of the superposed cylinder type the latch guards have alwayscalled for great care in manufacture and adjustment. They have also beena source of trouble and restriction in the design or lay-out of theneedle cam tracks, a frequent source of trouble in the running of themachine, an obstruction to the laying of the feed yarn into the needlehooks and an obstruction to the view of the knitting operation andaccessibility of various parts of the machine. Moreover, latch guardscause considerable strain to be placed upon the drawn stitch,particularly in the upper rib cylinder of a superposed cylinder machineand this is detrimental to the finished appearance of the face of thefabric.

The present invention overcomes all these disadvantages, and includesalso a knitting needle designed to facilitate this improved method offeeding yarn to the needle hooks, such a needle having a downturned noseportion of the hook so shaped and sufilciently long as to enable thefeed yarn to be received upon it above the latch, and a latch having itsfree end projecting outwardly beyond the front or nose of the hook to asufficient extent to catch the feed yarn when the latter is slid downthe front of the hook.

Preferably, the downturned front or nose portion of the hook is formedstraight and substan tially parallel with the back of the hook, and thelatch itself is short as compared with that of a needle of correspondingsize having the usual form.

In order that the invention may be more clearly understood, a preferredform of the invention will now be describedrwith the aid of theaccompanying drawings, in which Figure 1 illustrates a development'ofpart of a needle cam system for a superposed cylinder knitting machineoperating in accordance with the present invention,

Figure 2 is a side elevation of a preferred form of needle hook, and

Fig. 3 is a diagrammatic perspective view of some of the needlesillustrated in Fig. 1.

In Figure 1 the dotted line I represents the line of travel of theneedle butts in the operative or knitting track for the needles of thelower cylinder. Dotted line 3 shows the lineof travel of the same buttsin the out-oi-action track, and the dotted line 4 represents the line oftravel of the needle transfer butts in the normal out-ofaction positionof the needle. Dotted lines 2, 5 and 6 represent lines of travelcorresponding to lines I, 3 and 4 for the needles of the upper cylinder.It is assumed that the cams are stationary Y and the needle cylindersarerotating in the direction from right to left in Fig. 1.

In Fig. 1 some of the needles are shown in a purely diagrammatic manner,and the action of these needles will be those described hereinbelow.Fig. 3 on a much enlarged'scale diagrammatically illustrates a view oithe needles in the positions shown at the right-hand end of Fig. 1.

The letters A to I being employed to represent corresponding needles inboth these figures. In Fig. 3 a feeder is shown as having delivered yamto needle E, with the needles D and C just about to take the yarn.

The knitting butts of the needles which are in operation follow alongtracks I and 2 and in this which has been cleared of the latch into thehook when desired. This, for instance, is advantageous when making awelt of the type usual in circular knitting machines. The welt isgenerally made on a. 1 and 1 rib foundation, that is to say, alternateneedles are knitting in one needle bed and the in- V termediate needlesare knitting in the other neepostiion, on their approach to the knittingcams,

the needles carry the old loops round their stems below and clear of thelatches. Considering first the operation of the needles in the lowercylinder, the knitting butts first encounter fixed cam III by which theyare drawn downwardly to a position lb and at this height the old loophas just closed the latch of the needle but remains thereon, and thefeed yarn has been laid' on to the front of the needle hook above thelatch. Further travel of the needle brings its butt on to a slight riseon cam I I which raises the butt to the height lo and at this height thenew or feed yarn has slipped into the hook. The latch will have beenopened sufilciently either by the pressure of the feed yarn or bycentrifugal force and gravity when the raising of the needle eases theloop around the latch, or by a combination of both these effects. Theamount by which the latch will open will depend on the loop length ofthe old 100p and on the tension and elasticity of the yarn. Knitting camI2 then operates on the needle butts to move the needles so as to drawthe new yarn into a loop through the old one, and at the height Id thenew loop is fully drawn and the old loop has passed over the needle headinto the fabric. The needle is thereafter again raised to the height Ia.by cam I3 and the cycle of operations for knitting one stitch iscomplete.

The knitting butts of the needles in the upper cylinder which approachthe cam system at the height 2 follow through a similar cycle ofoperations with the aid of cams H, I5, I6 and II, the line of travel ofthe knitting butts of the active needles in the uppercylind er havingbeen given a similar notation in which the positions 2a, 2b, 2c and 2dcorrespond to the positions Ia, lb, I c, and Id respectively. In thelower cylinder as usual there are two stitch cams I2 and I8 respectivelyand a guard cam I9 which are adjustable for height to vary thestitch'length as required and in the upper cylinder the stitch cam I6and the guard cam are also adjustable for a similar purpose.

The knitting butts of those needles in the two cylinders which are to beretained out of action remain at a constant level indicated by the lines3 and 5.

In Figure 2 a needle is shown which is designed specially for use in themanner just described and comprises as usual a stem I20 on which is aknitting butt I2I and a transfer butt I22. The hook I23 is formed withan extended front or hook portion I24 which lies substantially parallelwith the back of the hook and is considerably longer than usual. Thelatch I25 is relatively shorter than needles in general use and projectsslightly beyond the front or nose so that the feed yarn which is laid onto the nose of the hook at a position indicated at I26 will, when theneedle is raised, engage the projecting lip of the latch and slipbetween it and the nose of the needle into the hook. Meanwhile, the oldyarn will be in the position indicated at I21.

The above-described method of operating the needle in relation to theyarn can be used not only in the feeding of a new yarn into the hook asjust described but also to return an old loop dle bed. During theknitting of the welt the needles of one bed, generally the lowercylinder, continue to knit normally, whilst in a selected course orselected courses those in the other needle bed retain their loops in thehooks but do.

not receive the new yarn. For this purpose it has been customaryhitherto to provide in the needle cam system a special welt trackextending all round the circle of cams in order to keep the needles inthe required positions to retain their loops. With the present method,however, it Is not necessary to have this special welt track except fora very short circumferential extent near the feed point. In the camsystem illustrated a welt cam, which is in the form of a bolt cam, isindicated at 2| and the needles approach this cam, after they have leftthe knitting cam system, at the normal knitting height. The cam 2| whenit is in operation returns the needles to a height 2; equivalent toheight 2b and at this point the old loop has been moved to encircle thenose of the hook above the latch. A movement obtained by means of guardcam 22 similar to that already described for feeding the new yarn thentakes place, that is to say, the needle butts are moved to a height 20at which the old 1001) will have passed into the hook of the needle,whereafter cam 23 withdraws the needle to a height 2h which representsthe usual welt position. At this height the needle then approaches theknitting cams but passes the feed point at a position that will causethe needle to miss the feed yarn and the needle will eventually bereturned to a height 2a by means of cams 24 and II.

The elimination of the welt track simplifies the cam system, not onlydirectly but it also avoids the necessity for providing movable camswhich'would otherwise be required to be out of action when making a weltand to be in action 4 when needles are being'taken across the welttrack.

A similar means of operating the needle to bring an old loop into theneedle hook may also be used with advantage for other purposes such. forinstance, as in a tucking operation.

A similar cam arrangement may be provided in the cam system for thecompanion needle bed, that is to say, for the lower cylinder in thespecific example illustrated, when a reverse welt is to be made.

0ther cams illustrated in the accompanying drawings form no part of thepresent invention and are concerned mainly with the transference ofloops from needles in one cylinder to needles in the other, and thistransfer system constitutes part of our co-pending application which hasmatured as U. S. Letters Patent No. 2,380,- 822, granted July 31, 1945.

We claim:

l. A method of knitting having an operational sequence which comprisesadvancing a needle to a height sufficient to clear an already formedloop below the opened latch of the needle. then retracting the needle toa height at which the feed yarn will be laid on to the nose of theneedle, subsequently raising the needle sufficiently to pass the newlyreceived yam into the hook of the needle and finally fully retractingthe needle to clear the old loop to the, back thereof.

2. A method of knitting according to claim 1 in which the latch, ifclosed, is opened'by the yarn itself during the raising of the needle tothe height which is sufiicient to pass the newly received yarn into thehook.

3. In a knitting machine, a series of latch needles, a needle cam systemcomprising successive cam elements and cooperating yarn feeding means,so constructed and arranged as to bring a previously formed loop held bya needle on to he outside of the latch therebyholding the latterresiliently closed, to lay the new yarn on to the front or nose of thehook of the needle while the latch is so held, and thereafter relativelyadjust the hook and the yarn to slide the latter between the latch andthe hook without materially opening the latch.

4. A method of knitting according to claim 1 in which when the needle israised sufliciently to pass the newly received yarn into the hook of theneedle this movement will bring the old loop previously held by theneedle on to the outside of the latch in order to hold the latterresiliently closed.

5. A method of transferring into the hook of a needle a previouslyformed loop held by that needle below its latch which consists inadjusting the height of the needle relatively tothe position of thepreviously formed loop so that the latter is first slid on to the noseof the needle above the latch whereafter a further movement of theneedle in a reverse direction slides the loop back into the hook of theneedle.

6. A method of knitting according to claim 1 in which the relativeadjustment 0! the hook and yarn to slide the latter between the latchand the hook occurs without materially opening the latch.

7. A method of forming a welt in which each needle approaches the weltcams at the normal knitting height and is operated by those cams to passthe old loop into the hook of the needle in the manner defined in claim9, and subsequently is returned to the normal welt track height.

8. A method of forming a welt in which each needle approaches the weltcams at the normal knitting height and is operated by those cams to passthe old loop into the hook of the needle in the manner defined in claim9, and subsequently is returned to the normal welt track height, thesaid needles being caused to travel at welt track height only betweenthe welt cam system and the knitting cam.

9. A method of forming a welt which comprises causing each successivelatch needle to approach the welt cams of a knitting machine at thenormal knitting height, moving the needle by means of a welt cam tocause the old loop to encircle the nose of the needle hook above thelatch, then moving the needle to a height at which the old loop willhave passed into the hook of the needle, and subsequently moving theneedle to normal welt track height. 7

10. A method of forming a welt according to claim 9 in which the needlesonly travel at welt track height between the welt cam system and theknitting cam.

ERNEST BROOKSBY. FREDERICK EDWARD DEANS.

